How to Query Specific Columns in Spring JPA?

Querying Specific Columns in Spring JPA

Spring JPA simplifies database operations, but retrieving partial data from a table can be confusing. This guide addresses the issue of selecting specific columns from a table using Spring JPA.

Consider the following scenario: You want to fetch only the projectId and projectName columns from the projects table.

SELECT projectId, projectName FROM projects

Solution: Utilizing Projections

Spring Data JPA provides projections to facilitate selective column retrieval. Here's how to implement projections in this case:

Create an interface that represents the required columns:

interface ProjectIdAndName {
    String getId();
    String getName();
}

In your repository, define a method that returns the projected data:

List<ProjectIdAndName> findAll();

By using projections, you can effectively select specified columns from a table in Spring JPA. This approach simplifies data retrieval by returning only the necessary attributes, enhancing performance and data privacy.

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